Wind Energy and Insects: The 'Little Things that Run the World'
by Margy Stewart
Too many people have a fairytale image of wind energy-as if it were a fairy godmother come to save us from climate change, those moving blades nothing more than her shimmering, diaphanous wings.
But her dazzling aura disappears once wildlife is considered. In the real world, heavy machines in constant motion do not alight softly on the land.
Indeed, we are just beginning to tally wind energy's toll on ecosystems. First, we learned about birds, how eagles and hawks were being killed. Then we learned about bats, how wind energy is driving their decline. (See "Will Bats Survive Wind Energy?" Common Sense Dispatch, April 2020.)
Now we are starting to learn about damage to a class of animals that, despite their lowly status, turn out to be essential to life on earth-Class Insecta, insects.
As far back as 2001, researchers discovered that industrial wind developments (IWDs) were killing insects in numbers large enough to hamper electricity production. Insect body parts-exoskeletons and hemolymph--were accumulating on the blades. Those remains roughened the surfaces and interrupted the air flows to the point that productivity could be reduced by half. This was considered an industrial problem, not an ecological one, as insect populations were assumed to be so large that they could easily absorb all the deaths from blades.
But a study published in 2018 found that turbine-caused mortality did pose population-wide threats to insects. Lead author Franz Trieb estimated that in Germany alone 1.2 trillion insects are killed every year by "wind parks" (as they're called in Germany). Trieb found that the cruising altitude for many insects coincides with the sweep of rotors. He documented "high insect concentrations worldwide at altitudes between 20 and 220 metres above the ground-the very same altitudes occupied by the rotors of wind turbines." He based his mortality numbers on analyses of insect residue scraped off of blades. The next step for researchers, he says, is to find a way to determine how many additional insects die of "barotrauma," the pressure differential between the leading and trailing edge of blades that has proven so deadly to bats, by causing their internal organs to collapse. (The remains of exploded insects are more likely to dissipate than leave an obvious trace, so innovative research methods would be needed to calculate their numbers.) Still, he found the mortality from direct strikes alone to be worrisome: "Such a large number of affected insects could be a relevant factor for the stability of the insect population and could thus influence species protection and the food chain," he concludes.
Other researchers have explored additional threats to insect populations. Beside blade contact and barotrauma, IWDs subject insects to light pollution. The lights atop wind towers, required by the FAA, are an annoyance to neighboring humans, who are irritated by the non-stop blinking. But the lights are more than an irritant to insects, whose lives are keyed to day-night cycles and who are often fatally attracted to lights. Artificial lights disturb every aspect of insect development, from emergence to mating to predator-avoidance. "The evidence that light pollution has profound and serious impacts on ecosystems is overwhelmingly strong," says the conservation group Buglife. Stating the problem even more starkly, a 2019 article in Biological Conservation describes light pollution as a "bringer of the insect apocalypse."
Indeed, that phrase, "insect apocalypse"--made famous in a 2018 New York Times Magazine article entitled "The Insect Apocalypse Is Here: What Does It Mean for the Rest of Life on Earth?"-indicates that we've moved way past the assumption that insect numbers are so vast that losses to IWDs make no difference. In a summary of recent research, author Brooke Jarvis describes the world-wide decline in the numbers of insects, posing a threat to ecosystems everywhere. With insect numbers plummeting, Jarvis describes fish scientists worried about mayflies and midges and bird scientists worried about caterpillars for baby birds. Indeed, ornithologists are now contemplating the possibility that the well-documented decline of bird populations is due not only to habitat loss but also to starvation. Fish and birds are part of an entire eco-universe that depends on insects. Paraphrasing entomologist Scott Hoffman Black, Jarvis writes, "We worry about saving the grizzly bear, but where is the grizzly without the bee that pollinates the berries it eats or the flies that sustain baby salmon? Where, for that matter, are we?"
Where, for that matter, are we? Black/Jarvis's final question is one we humans need to ask ourselves. Certainly, we depend no less than grizzly bears on a healthy ecosystem. Seventy-five percent of our food crops are insect-pollinated, and when Jarvis asked scientists to describe an insect-poor world, he heard words like "resource wars," "collapse," and "Armageddon." Yet it's the constant growth of our infrastructure--what Jarvis calls "the relentless expansion of human spaces"--that is causing the crises for wildlife and ultimately for ourselves.
No amount of fairy dust can make IWDs anything other than a part of this "relentless expansion of human spaces." People can argue that IWDs are or are not a genuine alternative to fossil fuels-but neither side should ignore the industrial reality of IWDs and their impact on the natural world.
Why believe in fairy godmothers when we still have so much to learn about the wondrous creatures that actually exist? Let's pay attention to our wild neighbors, for the more we learn about them, the more we learn about ourselves-and the better we can chart the best ways forward toward a rich and vibrant future. And while we're at it, let's show some appreciation for humble but helpful six-legged beings, some of whom really do have iridescent, diaphanous wings.